Method of preparing an aluminum sulphostearate



Patented Dec. 12, 1933 PATENT OFFICE METHOD OF PREPARING AN ALUMINUM SULPHOSTEARATE Alexander Horwitz, New York, N. Y.

No Drawing. Application May 8, 1929 Serial No. 361,550

1 Claim.

This invention relates to soaps and particularly metallic soaps prepared in such manner as to render the same insoluble in water; and the object of the invention is to provide a soap of the 5 class specified which by virtue of the manner of its preparation will materially increase the jellifying properties thereof in the preparation of products or compounds therefrom; a further object being to provide an improved means for sulphonating the stearic acidemployed whereby in combining the sulphonated product with certain metallic elements, such for example as aluminum sulphate, the resulting product in compounding with other suitable substances, will increase the jellification of the product produced or will increase the body consistency thereof in a simple and economical manner; and with these and other objects in view, the invention consists in a soap of the class and for the purpose specified which is simple in construction, efficient in use, and which is produced or compounded as more fully hereinafter described and claimed.

In accordance with the present methods, of sulphonating stearic acid, the sulphuric acid is introduced into a heated or melted body of stearic acid. In accordance with this process, a limited amount of sulphuric acid may be introduced by virtue of the fact that an excessive amount would develop charring or excessive discolorization to the product produced.

While I prefer to employ my novel or cold process, it will be understood that this process is only desirable and necessary where an excessive amount of the sulphuric acid is required to produce greater jelliflcation. In some instances, the heating process may be employed, and especially in such cases where the sulphuric content is smaller.

In producing my improved soap no definite proportions of the several ingredients as compounded can be given by virtue of the different conditions of the elements or compounds under process of production, but in order to give an approximate outline and proportion, the following is submitted:

Approximately Forty (40) parts of powdered stearic acid Approximately Forty (40) parts of sulphuric acid Approximately Five (5) parts of alkali Approximately Fifteen (15) parts of aluminum sulphate.

The above proportionate amounts will produce excessive jelliflcation by reason of the fact 55 that substantially equal parts of the stearic acid and sulphuric acid are employed. But, when a lesser amount of the sulphuric acid is employed, it will be understood that the alkali and metallic element such as aluminum sulphate will be proportionately changed. 69

At this time, it will also be well to state that I preferably employ a strong sulphuric acid of approximately 66 Baum, and the alkali employed will be preferably caustic soda in sufficient amounts to neutralize the sulphostearic acid.

In the preparation of the soap, I first place in a suitable vat or container, preferably of a shallow structure, the powdered stearic acid which is agitated or thoroughly stirred in, incorporating the sulphuric acid therewith, the latter be- 70 ing introduced slowly and being spread over the mass as much as possible to insure a thorough mixing of the ingredients. The resulting product will consist of a heavy viscous body, the complete preparation of which will be determined primarily from the uniformity in color of the entire mass.

The sulphostearic acid above referred to, is preferably produced under a cold process; but, as previously stated, when smaller amounts of the sulphuric acid are introduced, it may be prepared under heat at the melting point of stearic acid. The product as initially prepared is allowed to stand until the body consistency changes, and a thin crust forms on the top of the mass, at which time, the product is again stirred or agitated for approximately one hour, and again allowed to stand for a period of approximately twelve hours, after which the product is again stirred sufficiently long to thoroughly mix the same and to break up and incorporate the crust therewith. The entire body is then placed in a vat of cold water and washed therein by agitation or other means until all lumps that may prevail are broken up..

The water is then filtered off and fresh water introduced, and the above washing operation repeated in order to remove the free sulphuric acid which may prevail.

During the washing operation above referred to, the product is broken up into small bodies or particles and if desired and in order to insure the release or removal of the free sulphuric acid, the product may be ground in a wash bath so as to produce finer or more granular particles, per- 19;, mitting the water to more completely wash the product and remove the free acid, and this grinding is ultimately such as to reduce the product to substantially powdered form.

I next provide a neutralizing tank containing a weak alkali solution, into which tank, the powdered product is placed while being agitated, and sufiicient alkali is added to thoroughly neutralize the product. This last operation is preferably performed under heat and maintained under heat, approximately 200 Fahrenheit, until the next step in the process of forming the water insoluble soap is performed.

I next provide a tank or vat containing a suflicient amount of aluminum sulphate, dissolved in water under heat, at about boiling point, and into this product the heated sulphostearic acid soap water and may be packed in suitable containers for shipment or may be used immediately for the purpose of preparing various other products therefrom in which it is desirable to 'use a soap of the characteristics specified.

The water insoluble soap in question has unlimited uses, and for the purpose of illustrating some uses, it will be apparent that the same may be combined with various types of oils to increase the bodv consistency thereof, and further may be used in the preparation of greases, paints or other compositions of matter.

In practice, I have discovered that when stearic acid is previously treated with sulphuric acid and then used for making an aluminum soap, the resulting aluminum soap has certain superior characteristics. which are valuable in the manufacture of aluminum greases. Aluminum stearate made under the ordinary process has a main disadvantage in that it has been found that a large quantity of the mineral oil contained in such greases separates on standing, producing a very unstable grease. My product does not have this disadvantage in that it combines with the mineral oil making a more staple grease, eliminating to a large degree the separation of the mineral oil as above stated, and for that reason is more desirable. It is admitted that stearic acid cannot be sulphonated in the same way as an unsaturated or an oxy acid. However, it reacts with sulphuric acid under certain conditions to form addition products of the type illustrated as in the formula found on page 146 of Chemical Technology and Analysis of Oils, Fats, and Waxes, by Lewkowitsch, Fifth Edition, Vol. 1.

It will be understood that my invention is not necessarily limited to the specific ingredients herein referred to for the preparation of a soap of the class specified, nor am I limited to the proportionate amounts of the several ingredients herein set forth, it being understood that the amount of alkali and metallic element employed will depend largely upon the amount of sulphuric acid introduced with a given body of stearic acid, and various other changes in and modifications of the product and the method of its preparation herein disclosed may be made within the scope of the appended claims without departing from the spirit of my invention or sacrificing its advantages.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

The process of producing aluminum sulpho- 

